Choose origin, destination and departure time: the tool instantly computes the zones crossed, your flight direction (east or west), the estimated recovery length, and a day-by-day plan — when to seek or avoid light, your caffeine window, gradual sleep shifts, and meal and nap timing.
General jet-lag guidance, not medical advice. Consult your doctor if you have a sleep disorder or take regular medication.
Every output is computed deterministically from the inputs: zones = round(destination offset − origin offset) from our site’s timezone data. The recovery rule is a published rule-of-thumb from the jet-lag literature, applied as-is: ≈ 1 day per zone eastbound, ≈ 0.75 day per zone westbound. Daily advice follows stable research principles: bedtime shifted 30 minutes per day (published range 30–60), a caffeine window ending before 14:00 local, and a day-1 nap capped at 20–30 minutes for midday arrivals. Flight duration is estimated with the same distance model used by our flight-time calculators.
General jet-lag guidance, not medical advice.
Deep in your brain runs a roughly 24-hour body clock, tuned by light and meals to your home rhythm. Cross three or more time zones in one flight and you land still running on home time: the destination’s night is your brain’s afternoon, its first day your sleepless night. The result is night-time insomnia, daytime fog and poor concentration, and off-kilter appetite, digestion and mood. The symptoms are temporary by definition: they fade as the destination’s cues — sunlight, meal times, night darkness — re-set your internal clock, which is exactly what the plan above is built to accelerate.
Your body clock resists advancing far more than delaying. Flying east asks you to sleep and wake earlier than your body wants — to shorten your day — so eastbound symptoms last longer; hence a full day of recovery per zone. Flying west asks you to stay up longer — to lengthen your day — which the body tolerates far better, so roughly three-quarters of a day per zone usually suffices. Riyadh → Tokyo (6 zones eastbound) and a westbound Atlantic crossing come out of the calculator above as two completely different plans.
Three days out, move your bedtime and wake time 30–60 minutes a day toward destination time: earlier if flying east, later if flying west. Every hour you pre-shift at home is an hour you don’t suffer on arrival.
Your body clock resets to light more than anything else. Eastbound: avoid bright morning light during the first recovery days and seek afternoon sun; westbound: seek morning light and keep evenings dim. The daily plan above spells out seek/avoid for each day.
Caffeine shifts body clocks and boosts alertness, but timing is everything: one or two cups in the destination’s local morning only, last dose before 14:00. After that, half of it is still in your blood hours later and fragments the night sleep you need for re-entrainment. Skip alcohol near bedtime too — it fragments sleep and dehydrates you.
Set your watch to destination time as you board, then eat and sleep on that schedule from the first leg. Resisting (“I’ll sleep on home time”) stretches recovery; committing to the new clock shortens it by days.
If you land between midday and late afternoon destination time, take a single nap capped at 20–30 minutes and finished before 15:00. Longer or later naps drop you into deep sleep, steal the night’s rest and push your clock backwards.